Swedesboro, N.J. (CBS) — Veterinarian Karyn Collier, who works at the Saint Francis Veterinary Center, is trying to get to the bottom of a disturbing trend; dogs vaccinated against the flu are suffering from a flu-like virus.

After seeing numerous cases, she wonders, “Why are these vaccinated, well-cared for dogs still coming down with this illness?”

Dr. Collier says the first case she saw was back in May, and since then Saint Francis Veterinary Center has seen about 75 dogs with the same problem...